Re: [Xen-devel] [PATCH 1/3] Nested VMX: Check VMX capability before read VMX related MSRs.

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 05/09/13 03:57, Yang Zhang wrote:
> From: Yang Zhang <yang.z.zhang@xxxxxxxxx>
>
> VMX MSRs only available when the CPU support the VMX feature. In addition,
> VMX_TRUE* MSRs only available when bitt 55 of VMX_BASIC MSR is set.

As you already have to respin the patch, "bit" rather than "bitt"

~Andrew

>
> Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
> ---
>  xen/arch/x86/hvm/vmx/vvmx.c |   18 ++++++++++++++++++
>  1 files changed, 18 insertions(+), 0 deletions(-)
>
> diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
> index cecc72f..2e0b7f7 100644
> --- a/xen/arch/x86/hvm/vmx/vvmx.c
> +++ b/xen/arch/x86/hvm/vmx/vvmx.c
> @@ -1820,6 +1820,24 @@ int nvmx_msr_read_intercept(unsigned int msr, u64 
> *msr_content)
>      if ( !nestedhvm_enabled(v->domain) )
>          return 0;
>  
> +    /*
> +     * VMX capablitys MSRs available only when guest
> +     * support VMX.
> +     */
> +    hvm_cpuid(0x1, &eax, &ebx, &ecx, &edx);
> +    if ( !(ecx & cpufeat_mask(X86_FEATURE_VMXE)) ) 
> +        return 0;
> +
> +    /* 
> +     * Those MSRs available only when bit 55 of
> +     * MSR_IA32_VMX_BASIC is set.
> +     */
> +    rdmsrl(MSR_IA32_VMX_BASIC, data);
> +    if ( msr >= MSR_IA32_VMX_TRUE_PINBASED_CTLS &&
> +            msr <= MSR_IA32_VMX_TRUE_ENTRY_CTLS &&
> +            !(data & VMX_BASIC_DEFAULT1_ZERO) )
> +        return 0;
> +
>      rdmsrl(msr, host_data);
>  
>      /*


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